SELECTIVE CATALYTIC REDUCTION OF NO ON NH_4βCATALYSTS AT LOW TEMPERATURE

The selective catalytic reduction(SCR) of NO in oxygen excess is studied on beta zeolite in the NH + 4 form at temperatures from 30 to 250?℃ In absence of gaseous ammonia, the conversion of NO is 100% in the whole range of temperatures The reaction proceeds with the consumption of NH + 4 ions thereby converting the zeolite into its H + form The consumed NH + 4 ions can be easily replenished by admission of gaseous ammonia at reaction temperature or room temperature This reaction as present here might become a viable technology for removal of NOx at low temperature without addition of reducing agents In presence of ammonia, the complete conversion of NO is obtained above 230?℃ The mechanism of the SCR might be different in the presence and absence of gaseous ammonia The reaction is also found to proceed with good efficiency in the presence of SO2